The peculiar case of an insectivorous iguanid lizard that detects chemical cues from prey

Abstract

Ecological and phylogenetic factors determine which sensory modalities organisms use in their day-to-day activities. Among lizards, empirical studies indicate a tight association between foraging strategies and the ability to detect chemical cues from prey. Consequently, ambush insectivores do not detect food chemicals and these differences have a phylogenetic basis, as ambush lizards mainly belong to the Iguania clade. These data contrast, however, with the widespread uses of chemoreception in the Iguania genus Liolaemus, which are mostly insectivorous ambush predators. Moreover, observations from different Liolaemus species suggest a capability to find prey through chemoreception. In order to clarify the abilities of Liolaemus to detect chemical cues from prey, the chemoreceptive behavior of the insectivorous ambush predator, L. lemniscatus, was studied. Lizards were given the choice between areas with and without chemical cues from a food item (mealworms). Results show that test animals stayed for longer, moved more, and did more chemical exploration (tongue flicks) in the area where chemical cues from mealworms were present. Furthermore, in this area, more individuals displayed behaviors that suggest maintenance and defense of the prey patch. Thus, L. lemniscatus is the first insectivorous Iguania reported to be able to detect chemical cues from prey. Although I propose a mechanism for acquiring chemical detection of prey cues in Liolaemus, I also remark that it is necessary to reanalyze both the abilities to detect and use chemical foraging cues in Iguania at large, and the methodologies traditionally used to study these issues.

Susceptibility of lizards to predation under two levels of vegetative cover

“…Chemical communication in other iguanids is mediated by lizard's depositions (Labra, 2007;Wilgers and Horne, 2008). Neither depositions nor typical recognition behaviors (tongue flicking and gular pump) were identified during the trials which suggest chemical communication may not be relevant to our study.…”

“…There is good evidence that many species of lizards use chemical cues for some form of communication (Quinn and Hews, 2005;Labra, 2007;Wilgers and Horne, 2008), potentially affecting the behavior of individuals during the trials. Chemical communication in other iguanids is mediated by lizard's depositions (Labra, 2007;Wilgers and Horne, 2008).…”

Supplementation of Male Pheromone on Rock Substrates Attracts Female Rock Lizards to the Territories of Males: A Field Experiment

“…Similarly, insectivorous Liolaemus lemniscatus lizards stay for longer and do more chemical exploration in areas where chemical cues from mealworms are present [66]. Females of other animals, such as some moths or crickets, may also be attracted to food chemicals provided by males of their own species in their pheromones or nuptial food gifts [67], [68].…”

“…Alternatively, females might be attracted to ergosterol per se because this could be a food stimulus indicating the presence of food, and females might have a sensory bias for this chemical food stimulus independen of the male signal, as has been suggested in a previous experiment with this lizard species [32] . Similarly, insectivorous Liolaemus lemniscatus lizards stay for longer and do more chemical exploration in areas where chemical cues from mealworms are present [66] . Females of other animals, such as some moths or crickets, may also be attracted to food chemicals provided by males of their own species in their pheromones or nuptial food gifts [67] , [68] .…”

Population Scent Discrimination in Two Liolaemus Lizard Species: Exploring Ethological Isolation

“…This study explored evidence of ethological isolating barriers in Liolaemus species by investigating population scent discrimination in closely located populations of two species, L. tenuis and L. lemniscatus. These are common species of central Chile [19], and evidence indicates that scents play an essential role in different daily contexts [31,34,[44][45][46]. Therefore, for these species, scent population discrimination may be relevant.…”